The family of former NFL star Aldon Smith is donating the player’s brain to the Boston University CTE Center to research the effects of repetitive brain injuries.

The 36-year-old died suddenly on Saturday, hours after delivering pizzas to a homeless charity in the San Francisco Bay area. No cause of death was given and Smith’s family has hired attorneys Harry Daniels, Bakari Sellers and Wayne Kendall to investigate his death.

“As with anyone who dies so suddenly at such a young age, we understand that there is a great deal of interest in and speculation about Aldon Smith’s passing and we intend to get to the bottom of it,” the attorneys said in a statement released Tuesday. “To that end, we have taken a number of steps including sending his brain to Boston where medical experts will examine it for CTE as well as other damage caused by years of concussions and additional trauma.

“In the meantime we simply ask you to keep Aldon’s family in our prayers and respect their privacy as they struggle to come to grips with this terrible loss.”

CTE, a degenerative brain disease, can only be diagnosed after death and has higher rates among athletes in contact sports than in the general population. Its symptoms include depression and mood swings.

Smith’s friend, Amir Shirazi, told the San Francisco Chronicle, that he found Smith slumped over in the front passenger seat of his car after the former San Francisco 49ers had delivered the pizzas on Saturday. Smith was taken to hospital and was declared dead.

“He was a creative mind, so smart, so fierce, so real, so powerful, his presence, his passion and his aura meant a lot to me as a brother and I wish I could’ve did more to help him and pray to God he doesn’t have to hurt anymore,” his former teammate, Anthony Dixon, wrote on social media.

Smith played six seasons in the NFL for the 49ers, the Raiders and the Cowboys. The 49ers, who selected him with the seventh overall selection in the 2011 NFL draft, reached the NFC title game in his first three seasons, with one trip to a Super Bowl.

Smith recorded 14 sacks and 27 quarterback hits in his rookie campaign and was second in Defensive Rookie of the Year voting. In 2012, his second season, he had 19.5 sacks – still a 49ers franchise record – and 29 quarterback hits in the best campaign of his career, earning All-Pro and Pro Bowl honors as the 49ers reached the Super Bowl.

But off-field issues slowed his career, including multiple arrests on suspicion of driving under the influence and an arrest in 2013 on felony charges of possessing illegal assault weapons. He was released by the 49ers in 2015 after an arrest for DUI, hit-and-run and vandalism. He was suspended multiple times by the NFL for violating the league’s personal conduct and substance abuse policies. After playing a final season with the Dallas Cowboys in 2020, he formally announced his retirement in 2023.

The 49ers paid tribute to Smith on Saturday in a team statement. “We are devastated by the sudden and tragic passing of Aldon Smith,” the 49ers said. “Aldon’s undeniable talent and sheer dominance on the field were on display from the moment he joined our organization, having recorded one of the best rookie seasons the National Football League has seen. Beyond his excellence as a player, Aldon will be remembered for his infectious smile that lit up every room he walked into. Our entire organization sends its deepest condolences to the Smith family and all who knew and loved Aldon.”